Section 28-5807 - Registration period; proration; retroactive collectionA. The director shall initially register a vehicle with a registration expiration of twelve months from the last day of the month in which the vehicle was initially purchased.B. The director may register or reregister a vehicle for less than twelve months and prorate the annual vehicle license tax if the director determines proration tends to fulfill the purpose of the monthly registration system.C. The director shall not collect a vehicle license tax retroactively for any period that the vehicle was not registered if the current owner of the vehicle was not the owner of the vehicle during any part of the period in which the vehicle was not registered.